In recent years, technological development has been being made extensively about flexible electronic devices having high flexibility. Examples of such flexible electronic devices are a device as typified by an IC card which is formed by transferring a transfer subject substrate which is a thin-film silicon wafer formed with integrated circuits (ICs) to a transfer destination substrate which is a flexible resin substrate and a flexible liquid crystal display device, which is light in weight and less prone to break, and is formed by transferring a thin-film transfer subject substrate formed with thin-film transistors (TFTs) to a transfer destination substrate which is a flexible resin substrate. In particular, a human interface device in which a displacement, a displacement speed, or the like of a bend of the display device is detected as a variation in electrical property and a desired image is displayed according to the detected variation is known as an example of such a flexible liquid crystal display device. For example, in a case where an e-book is configured by using this display device, it is possible to change the image that is displayed on the display device by performing a page turning-over operation on the display device. An example of such device is disclosed in JP-A-2004-046792.
In general, such a flexible electronic device which is high in flexibility is configured by a method called a transfer method (refer to JP-A-2007-088235, for example) The transfer method is the following method. Electronic circuits are formed in advance on an inorganic substrate that is high is heat resistance. Then, a thin-film transfer subject substrate is formed by peeling a surface layer that is formed with the circuits off the inorganic substrate or thinning the inorganic substrate which is formed with the circuits from the back side by etching or the like. The back surface of the thus-formed thin-film transfer subject substrate is coated with an adhesive layer and the transfer subject substrate is bonded to the front surface of a transfer destination substrate.
Incidentally, to construct a flexible electronic device that is as thin as paper by the above-described transfer method, it is necessary that the transfer method be implemented by a process that is executed at as low a temperature as possible because the transfer destination substrate is mainly made of plastics which is low in heat resistance.
Among known methods for constructing a flexible electronic device by the transfer method as implemented by a low-temperature process are the following methods.
In one method, an organic semiconductor is used which can be formed by an ordinary temperature/pressure process such as spin coating or printing. An example of such method is disclosed in the following documents (1) and (2).    Document (1): D. Gundlach et al., Tech. Dig.-Int. Electron Devices Meet. (1999), pp. 111-114.    Document (2): T. N. Jackson et al., SID '00 Dig. (2000), pp. 411-414
Another method (called FSA) is as follows. A single crystal silicon wafer on which semiconductor circuits or semiconductor integrated circuits are formed is cut into chips, which are dispersed in a fluid. A plastic substrate having recesses at prescribed positions is immersed in the fluid, whereby single-crystal chips are fitted into the recesses in a self-aligned manner. An example of such method is disclosed in the following document (3).    Document (3): S. Drobac, SID '99 Dig. (1999), pp. 12-16
In particular, the method disclosed in the document (3) is effective because no limitations are imposed on the material of the transfer destination substrate and low-melting-point materials such as plastics can be used.
However, electronic devices produced by the above-described transfer method have a problem that when they are stored at high temperature cracks may develop in the transfer subject substrate because of thermal stress occurring parallel with the boundary surface due to a difference between the thermal expansion coefficients of the transfer subject substrate and the transfer destination substrate.